(1) Field of the Invention
This invention relates to an apparatus for regenerating fluidizing medium. More particularly the invention relates to an apparatus of regenerating the fluidizing medium employed in a fluidized-bed incinerator, wherein the sticking matter attached to the fluidizing medium employed in the incinerator in the process of burning up in the incinerator the ash collected from power plant boiler exhaust gases (hereinbelow referred to as "EP ash") is removed from the fluidizing medium chemically and physically.
(2) Description of the Prior Art
From boilers burning large amount of crude heavy oil, such as those of large thermoelectric power plants, is discharged EP ash, i.e., heavy oil ash containing unburned carbon. When this EP ash is disposed of as refuse, it usually is not suitable for filling-up due to the peculiarity of its properties. Therefore, it has to be disposed of by specified persons, in many cases. There arise many problems such as increase in the cost of transportation and difficulty of handling due to its pulverized state. In view of this, as incidental equipment for large-size boilers that cause these problems have been developed apparatuses that solve or alleviate these problems by burning up the EP ash and achieving reduction in volume and weight. These apparatuses are advantageous in that vanadium compound contained in the EP ash is concentrated and thus concentrated vanadium compound can be appraised equally to vanadium ore. Therefore, there is an added value that its recovery is enhanced.
These apparatuses include various types of incinerator furnaces: for example, cyclone type, rotary kiln type, stoker type and fluidized-bed type. However, it is well known that each of them has both merits and demerits and that it is not easy for them to burn up the EP ash. Out of them, the apparatus that uses a fluidized-bed furnace to treat the EP ash is regarded as important because it has relatively good adaptability to variations in load and ash content. However, even this fluidized-bed incinerator has the following drawbacks. That is, the fluidizing medium (an active or inactive substance comprising sand or CaO as its main component) thickens with time due to the adhesion of sticking matter and fails to flow smoothly, so that long-term continuous operation of the incinerator becomes difficult. This makes it necessary to stop the incinerator to renew the fluidizing medium.
Therefore, there are disadvantages in terms of operation efficiency, operating cost, cost of medium and the like, and it is desired to eliminate these disadvantages.